What health concerns would you be talking about. I have several females that produced very well from 4.5" and has they got bigger they became worse mothers. The clutches might be smaller when the T is smaller but other then that I dont see any outstanding health concerns.Can a thirteen year old girl become pregnant? Sometimes, but it isn't exactly the best idea as far as health is concerned.
OK...anyways. This discussion isn't about humans, and I've yet to see any studies about whether or not breeding affects female tarantula health (although, breeding is occasionally hazardous to male T health ) so anything anyone says from this point is speculation unless you can dig up a research paper.Say a T is one shed away from becoming the adult size her species should reach, can she produce a case. Say the adult size is 6" and she's 5".